Remote-control unit



Patented Jan. 17, 1950 REMOTE-CONTROL UNIT Willard C. Hall, Los Angeles, Calif., assignor to Helen D. Hall and Willard C. Hall, copartners doing business as Electronic Enterprises, Los

Angeles, Calif.

Application February 18, 1948, Serial No. 9,150

Claims.

This invention relates in general to remote control devices and the present application is somewhat related to my co-pending application for Automatic impulse timer and control circuit, Serial No. 722,355, filed January 16, 1947, now abandoned. More specifically, my invention pertains to a remote control unit comprising an actuating device or transmitter which momentarily introduces a unidirectional current, such as a pulsating direct current, into a line circuit in which alternating current is normally flowing as, for example, an alternating current power line, and a responsive device or receiver which receives the unidirectional current component in the line and is controlled thereby.

It is a primary object of my invention to provide a remote control unit which utilizes an alternating current line, for example, the conventional two-conductor, 110 volt house line, as a medium for the transmission of a pulsating direct current from the actuating device to the responsive device of such unit, without affecting the operation of various alternating current devices which may be connected to such line and drawing current therefrom.

It is an additional object to provide in such a unit an actuating device and a responsive device both of which are connected across the alternating current line to operate in parallel with the alternating current power source, thus eliminating the necessity of breaking the alternating current line for the purpose of placing either the transmitter or receiver in series therewith. In this connection, it is a further object to provide actuating and responsive components which may be plugged into the conventional outlet of an alternating current house line and operate therefrom.

It is a further object to provide a transmitter for such a unit which rectifies alternating current from the line to provide the unidirectional current which controls the receiver, thereby drawing all power for the operation of the unit from the alternating current line which serves as the transmission medium for the unidirectional current impulses.

It is a further object to provide a highly sensitive unit of this character so that the receiver may be controlled by the transmitter when separated an appreciable distance therefrom, as for example, when the receiver is plugged in at a second floor bedroom of a house and the transmitter is located in the first floor kitchen. It is an additional object to furnish sensitivity regulating means in conjunction with the receiver whereby it is possible to selectively control one or more such receivers at varying distances from the transmitter without affecting another such receiver, as for example, a receiver located in a neighboring house, which although separated from the transmitter by isolation transformers may otherwise be responsive thereto.

It is an additional object to provide in an alternative embodiment shown, a transmitter which selectively introduces into the line a pulsating direct current in either direction of flow and a receiver which is polarized so as to operate one load when such pulsating direct current is in one direction in the line and a separate load when such current is in the opposite direction.

It is a further object to provide a compact and portable remote control device which is both simple and inexpensive to construct and requires no special installation for operation.

My invention achieves its objects by the use of a transmitter which includes a rectifier connected across the alternating current line and which is operative to load the line with a relatively small unidirectional current when its switching means is closed. My receiver, which is likewise connected across the line, includes a relay in series with a sensitive, variable impedance current path. Normally, due to the magnitude of this impedance, no appreciable flow of current across the line through the relay occurs. However, when a relatively small unidirectional current is introduced into the line by the transmitter, this high impedance current path is materially lowered and the relay actuated, which in turn completes the circuit to the load.

In the alternative embodiment, the unidirectional current may be polarized in either direction by the transmitter and affects selectively either of two variable impedances in the receiver to actuate a switching relay controlling the circuit to two different loads.

Further objects of my invention will appear from the following specification and the drawing which shows three embodiments of my invention for the purpose of illustration only and in which:

Fig. l is a circuit diagram of my remote control device connected in parallel with an alternating current power source through a two-conductor alternating current power line;

Fig. 2 is a similar circuit diagram showing an alternative embodiment of the receiver which includes a saturable reactor as a variable impedance means; and

Fig. 3 is a similar circuit diagram showing an 3 alternative embodiment for selectively controlling two separate loads.

Referring to Figs. 1 and 2 of the drawing, I show in each instance a two-conductor alternating current power line H, carrying alternating power from a source, across which is connected an actuating devic or transmitter including the components shown within the dotted line area indicated generally at I3.

In the dotted line area indicated generally at I there is shown a responsive device or receiver together with a load 30 which is controlled by th responsive device in the manner hereinafter described.

The transmitter I3 includes a half-wave rectifier l6 which is connected through a currentlimiting resistor II to one side of the alternating current line II and through a switch l8 to the other side of the line H.

The half-wave rectifier I6 may be any variety such as a mechanical, metallic or electronic valve, although I prefer to employ a metallic rectifier of copper oxide or selenium and I have found the latter particularly suitable for this use because of its ability to withstand relatively large momentary overloads. Since the rectifier l6, regardless of type, possesses negative resistance characteristics, the resistor II, which, for example, may be a 50 watt, 10 ohm, D, C. resistor, is placed in series therewith to limit the current through the rectifier. For example, if a resistor ll of the rating indicated above is used in conjunction with a ie ampere selenium rectifier I6, the unidirectional current across the line I will build up to a value of approximately 1 ampere on momentary closure of the switch l8, which current is ample to actuate the receiver l4 when the latter is separated a considerable distance from the transmitter.

Likewise, the switch I8 may be of any variety but I prefer to employ a through-type switch in order to prevent overload of the rectifier IS in case of switch failure.

The receiver 4 shown in Fig. 1 includes a variable impedance circuit shown generally at connected directly to the line H at one side and through a circuit closing relay 2| having a variable resistor 22 in parallel therewith, to the opposite side of the alternating current line H. A load 30, represented for illustration as an incandescent lamp, is connected across the line H through the trip circuit of the relay 2|, completing the circuit through the load when the relay armature 23 is positioned against the relay contact 24.

The variable impedance circuit 20 includes a capacitor 25 and an inductor 26 in parallel, forming a resonant circuit presenting a substantially infinite impedance to the flow of alternating current across the line I I and through the relay 2|. Although a fundamental or any low harmonic frequency of the alternating current in the line Il may be selected with satisfactory'results, I prefer to pretune the resonant frequency of the variable impedance circuitZIi to the second harmonic of the frequency of the alternating line current in order to obtain relatively high sensitivity to the unidirectional current from the transmitter I3 together with maximum impedance to the fiow of alternating current across the line II when such unidirectional current component is not present. Thus, I have obtained excellent results when the line current was 60 of the iron-core type having an inductance of 4 4.5 henrys and a capacitor 25 of i microfarads, which together form a circuit resonant at about 38 cycles.

The relay 2| may be of varying sensitivity according to the contemplated distance of separation between the transmitter and receiver, the presence of intervening inductances, and the size of the variable resistor 22 shunting it. I have found, for example, that when the transmitter l3 and receiver I4 are both located within one conventional sized house with no intermediate isolation transformers in the line I I between them, a relay 2| having a D. C. resistance of approximately 15 ohms and closing when a current of approximately .5 ampere fiows through its coil circuit, is suitable. When such a relay 2| is shunted with a variable resistance 22 of, for example, 200 ohms D. C. resistance, a wide range of sensitivity adjustment is obtainable, permitting the selective operation of one or more of a plurality of receivers within a given building or distance. In the event operation between buildings through an interposed isolation transformer is desired, a more sensitive relay 2! and larger shunt 22 may be required.

Referring to Fig. 2, the circuit illustrated differs from that of Fig. 1 in the employment of a saturable reactor as the variable impedance circuit 20 comprising a control winding 28 and a controlled reactance 21. The latter is connected directly to one side of the alternating current line I I and through the circuit closing relay 2| to the opposite side of the line. The control winding 2B is connected across the line H through the variable resistance 22.

The embodiment of my invention shown in Fig. 3 includes a transmitter shown generally at 33 having a pair of half-wave rectifiers 35 and 36a, each connected across the alternating current line 3| through the respective currentlimiting resistances 31 and 31a and switches 38 and 38a. The half-wave rectifiers 36 and 360. are oppositely polarized, each permitting a, flow of current in a counter direction to the other.

The receiver, including two loads 50 and 50a, is shown within the dotted line area indicated generally at 34. 5| and 5|a are a pair of variable impedance circuits, the former, including an inductor 453,116. a capacitor 45 in parallel therewith to form a resonant circuit, being connected across the line 3| through the coil 4| of a latching relay 49 and a variable resistance 42. The variable impedance circuit 5|a includes a capacitor 45a and an inductor 46a in parallel therewith similarly connected through a variable resistance 42a. and a relay coil Ma across the line 3|. A half-wave rectifier 53 is interposed between the variable impedance circuit 5! and the relay coil 4| and similarly a half-wave rectifier 52 is connected between the variable impedance 5|a and the relay coil 4|a, but oppositely polarized to the half-wave rectifier 53.

The latching relay 49 has a common armature 43 which may pivot between contacts 44 and 44a to connect the load 50 or 50a respectively across the line 3|. Relay latches 54 and 54a retain the armature 43 in closed or contact position after initial deflection and until the armature 43 is drawn by the coil 4| or 4|a to the opposite position.

In operating the remote control device shown in either Fig. 1 or 2, the transmitter 13 and receiver M are connected to the line H by a consuitable location, each, for example, within separate rooms of a house. The devicejto be controlled, for example aradio receiver connected to the line H in the usual manner, may contain an on-off switch or latching relay to be activated by a momentary electrical fiow through the relay, or a latching relay may be included in the receiver itself in the'manner illustrated in Fig. 3.

To actuate the remotely located device, the operator closes the switch l8 which causes a current to flow through the half-wav rectifier l6 and resistor H across the line. Such current flowing through the receiver l3 will be a pulsating direct current of a frequency one-half that of the alternating current in the line H. I am of the opinion, although I do not wish to be bound thereby, that such unidirectional current acts upon the conventional alternating current in the line II to alter or distort the normal sine wave form of such current to an irregular wave having a diminished negative amplitude. In any event, the unidirectional current introduced into the line H, materially lowers the impedance of the variable impedance circuit 2Uof the receiver 14, permitting alternating current from the line I i to flow through the relay 2| across the line H.

In the device shown in Fig. l where the inductance 26 and the capacitor are normally pretuned to a resonant frequency barring the fiow of alternating current across the line H, the unidirectional current introduced into the line by the transmitter has the eifect of throwing this impedance circuit 20 off resonance, permitting the flow of alternating current through the relay 2|. In the device illustrated in Fig. 2, but little current normally flows across the line H through the saturable reactor. In this circuit the introduction into the control winding 28 of the unidirectional current component radically reduces the impedance of the saturable reactor and similarly causes a current flow through the relay coil 2 l. In both instances, provided the sensitivity control, viz., the variable resistor 22, is properly adjusted, the current flow through the relay 2! will draw the armature 23 to the contact 24, completing the circuit to the load 30 or a suitable switching means in the device to be controlled.

In the embodiment shown in Fig. 3, the closure of the switch 38 will lower the impedance of the variable impedance circuit 5! to operate the relay 4i and load in the manner indicated above,

but will leave unaffected the variable impedance circuit Sic, due to the oppositely polarized halfwave rectifier 52. Similarly, the closure of the switch 380. will notaffect the variable impedance circuit 5|, since the unidirectional current thus introduced is blocked by the half-wave rectifier 53 from flow through this portion of the receiver 34 but load 50a will be actuated in the manner previously described. Thus, it is apparent that each switch 38 or 38a will affect only one of the loads 50 or 59a, respectively, to permit selective multiple control.

I have found that both variable impedance means illustrated and described above, namely, the resonant circuit and the saturable reactor, are extremely sensitiv and will be afiected by the unidirectional current from the transmitter at considerable distances therefrom. Moreover, I have, with the use of my invention, controlled receivers located within other buildings from that in which the transmitter is located, even in instances where an isolation transformer intervenes between the two. In order to regulate and decrease sensitivity and avoid undesired actuafrom by electrical means.

tion of any receiver by a foreign transmitter, I have provided a variable resistor 22 in the circuit shown in Fig. 1 which shunts the relay 2| to the extent desired to limit relay response to a current of a minimum magnitude. In the circuit illustrated in Fig. 2 the variable resistance 22 serves to limit, as desired, the flow of the unidirectional current through the control coil 28, thus varying the magnitude of the unidirectional current required to lower the impedance of the saturable reactor to the required degree. Similarly, in Fig. 3, the variable resistors 42 and 42a control the fiow of the unidirectional current through the variable impedance circuits 5| and 5m, respectively.

I have also found that the operation of my receiver and transmitter does not affect the functioning of any other alternating current devices connected to the line and operating therefrom. In addition, both my receiver and transmitter contain no large or bulky components but each is capable of being housed in a small portable case for easy movement and connection to a line in a wide variety of useful locations wherever outlet plugs exist.

Although I have described my invention in connection with its use in a household to remotely control various electrical devices, wherein such operation may be from a conventional volt, 60 cycle house current line, it is apparent to anyone skilled in the art that my invention is equally applicable to a wide variety of uses where mul tiple phase systems are employed or a less conventional type of alternating current power is supplied as, for example, 400 cycle alternating current. Moreover, my invention is useful in a wide variety of commercial and industrial applications as, for a single example, to fire photographic flash bulbs at a remote location there- Accordingly, such description is intended for illustrative purposes only and I do not wish to be limited thereby but wish to be accorded the full scope of the following claims.

I claim as my invention:

1. In an arrangement for energizing apparatus connected to an alternating current line through which alternating current is normally flowing by unidirectional current impulses: a circuit closing relay for completing the line circuit to the apparatus to be energized; and variable impedance means connected in series with said relay to provide electrical isolation of said relay from the alternating current in the line, said means comprising a saturable reactor responsive to the unidirectional current impulses to permit the flow of alternating current through said relay.

2. In a remote control unit for use in combination with an electrical alternating current supply line; an alternating circuit having a ground wireand a live wire, a transmitter including a half-wave rectifier, a switch means, and a resistor means in series and connected across the ground and live wires; a receiver including a variable impedance system having one end thereof connected to the ground wire and the other end thereof connected to the live wire, the system consisting of a tuned circuit in series with a parallel connected circuit having in one of its conductor paths the coil of a relay unit and in the other conductor path a resistor means.

3. The control unit recited in claim 2 wherein the rectifier is a selenium cell and the impedance is an induction coil having a rating of about 4.5

7 henrys and a condenser having a capacitance, of-

rent in the receiver is kept at an immaterial value but permitting direct currents from the transmit-j ter to, enter and operate the coil of the relay.

4. The-control unit recited in'claim 2 wherein the rectifier is a copper oxide pile andthe receiver impedance a small tank circuit having an induction coil and a condenser, anda current load having one side thereof connected to the ground wire, a switch operable by the relay unit" having one side thereof connected to the load and the other side thereof connected to the live'wire.

5. In a direct current means for remotely controlling the operation of an electrical load; a pair of electrical conductors carrying alternating current, an electrical load having one electrical side thereof connected to one of the conductors and another electrical'side thereof connected to one electrical side of a switch, and means connecting the other electrical side of the switch to the other one of said pair of conductors, a relay coil for operating the switch, and a resistor in parallel therewith forming a double electrical path, a tuned 8: current regulator in series connection with the mentioned doubleelectrical path which provides a series-parallel hook-up, this hook-up having its ends electrically connected between the said pair of conductors; and a multiple connected rectifier, signal switch and resistor connected between the pair of conductors at some remote point thereof which causes electrical pulsations independent of the alternating current which pass through the conductors and through the relay coil to operate it when the signal switch is closed.

WILLARD C. HALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 20 1,778,465 Ozanne Oct. 14, 1930 1,834,771 Eastman Dec. 1, 1931 2,213,384 Conwell et a1 Sept. 3, 1940 2,303,786 Bonnano Dec. 1, 1942 

